Part 1: The Deep Circulation of The Ocean

Question:

How does the temperature of water affect ocean circulation?

Hypothesis:

________________________________________________________________________ (warm water)

________________________________________________________________________ (cold water)

Control: Room temperature Water

Independent Variable: ______________________________________________________

Dependent Variable: _______________________________________________________

Materials

Room temperature fresh water200mL cold water200mL hot waterSalt

Red food coloringBlue food coloringShoebox sized plastic binbeakers

Procedure:

1. First make sure you have read over this entire lab2. Identify the independent and dependent variable(s)3. Make 2 hypotheses using an “if and then” statement (there is room for this above). One should

be about what will happen to your cold water and the other will be about what will happen to your warm water.

4. Fill a transparent plastic bin with 2000mL room-temperature water5. Measure and add 70g of salt. Stir to dissolve the salt. This represents the ocean at 35‰6. Prepare cold ocean water by measuring 200mL of cold water and adding 7g of salt. Color with

blue dye and stir.7. Prepare warm ocean water by measuring 200mL of warm water and adding 7g of salt. Color

with red dye and stir.8. Record the temperatures of the 3 different containers of water in the data section and take

observations/drawings of the appearance of the water in your bin before making any changes9. Slowly add your warm ocean water from the right hand side of bin while slowly adding your cold

ocean water from the left hand side of the bin. Record your drawings/observations about what you see

10. Wait one minute and take additional drawings/observations11. Wait three minutes and take additional drawings/observations

Data:

Water Temperature (⁰C)Room Temperature SeawaterHot SeawaterCold Seawater

Drawings/Observations

Before

During

1 min later

3 min later

Questions:

1. How did your results compare to your predictions? Explain any differences.

2. What do you think would happen if you made the hot water hotter or you made the cold water colder? Explain.

3. Write a procedure for how you would set up this new investigation (based upon your answer to #2)

4. How is this investigation related to deep ocean currents in our oceans? (hint: think temperature, density, and salinity)

Part 2: The Deep Circulation of The Ocean

The properties of different water masses in the Atlantic and Pacific Oceans are shown in the data tables below. The simplified cross sections of both oceans are shown below in figures below these. Use your understanding of the factors that influence ocean circulation to fill in the names (abbreviations) of the water masses on the figures and answer the following questions.

ATLANTIC OCEANWater Mass Temp (°C) Salinity (ppt) Density (g/cm3)Antarctic Bottom Water (AABW) -0.5 34.7 1.0278Antarctic Circumpolar Water (AACP) 0 34.7 1.0272Antarctic Intermediate Water (AAIW) 4 34.2 1.0269North Atlantic Deep Water (NADW) 3 34.9 1.0276

PACIFIC OCEANWater Mass Temp (°C) Salinity (ppt) Density (g/cm3)North Pacific Intermediate Water (NPIW) 5 34.2 1.027Antarctic Circumpolar Water (AACP) 0 34.7 1.0272Antarctic Intermediate Water (AAIW) 4 34.2 1.0269North Pacific Deep Water (NPDW) 3 34.6 1.0273

1. Temperature and salinity are the two primary factors controlling the density of a water mass. Based upon this knowledge, propose several ways that these factors could change, thereby changing the density of the water mass.

2. How could these factors affect ocean circulation patterns?

3. Does wind affect deep ocean circulation? Explain.

4. Another word for deep ocean circulation is “thermohaline circulation” or the “the great ocean conveyor”. Why would ocean circulation be described as a conveyor belt? What is being moved on this conveyor belt?

5. Some scientists believe that changes in the density of water masses may cause abrupt and sudden climate change. Why do they believe this? Summarize their argument.

6. What is upwelling? Explain.

****Resources that may help you****

http://www.windows.ucar.edu/ (there is a search box in the lower left that will lead you to articles just on this site)

http://www.youtube.com/watch?v=3niR_-Kv4SM http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/eln/upw.rxml http://www.classzone.com/books/earth_science/terc/content/visualizations/es2405/

es2405page01.cfm?chapter_no=visualization